release upgrade breaks internet and other things

[Tom H]

On Wed, Oct 3, 2018 at 7:27 PM Volker Wysk <post at volker-wysk.de> wrote:
>
> I've done a do-release-upgrade on my 16.04 LTS system. This has broken
> the internet connection, and more. I get immediate "unknown host"
> errors when I ping to any host. When I lookup an adress in Firefox, I
> get a "Page not found, The connection to the server ... failed."
>
> Sorry, I don't know how to troubleshoot this connection problem.
>
> Where should I look..?
>
> Should i even look, or would it be easier to reinstall everything in a
> new 18.04.1 system from scratch? (This would be quite a few things.)

Previous upgrades with network problems turned out to be dns problems.
/etc/resolv.conf" was a symlink pointing at the wrong file, IIRC.

Is it a file or a symlink?

If a symlink, to which file is it pointing?

What are the name servers?